perspective and blurred wall structure of the fronhas dam in a valley with the river alva, arganil portugal

aerial alva architecture arganil beira blurred cliff coimbra concrete construction cortiça countryside dam ecological electric electricity energy engineering environment environmental europe flow forest fronhas hill historical hydraulic hydroelectric hydropower industrial industry landscape martinho mountain nature outdoor perspective pombeiro portugal portuguese power production reserve reservoir resource river sao source station structure turbine valley view viewpoint wall water